1 /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
2 /* Copyright (c) 2018 Facebook */
3 #ifndef _UAPI__LINUX_BTF_H__
4 #define _UAPI__LINUX_BTF_H__
6 #include <linux/types.h>
8 #define BTF_MAGIC 0xeB9F
19 /* All offsets are in bytes relative to the end of this header */
20 __u32 label_off; /* offset of label section */
21 __u32 object_off; /* offset of data object section*/
22 __u32 func_off; /* offset of function section */
23 __u32 type_off; /* offset of type section */
24 __u32 str_off; /* offset of string section */
25 __u32 str_len; /* length of string section */
28 /* Max # of type identifier */
29 #define BTF_MAX_TYPE 0x7fffffff
30 /* Max offset into the string section */
31 #define BTF_MAX_NAME_OFFSET 0x7fffffff
32 /* Max # of struct/union/enum members or func args */
33 #define BTF_MAX_VLEN 0xffff
35 /* The type id is referring to a parent BTF */
36 #define BTF_TYPE_PARENT(id) (((id) >> 31) & 0x1)
37 #define BTF_TYPE_ID(id) ((id) & BTF_MAX_TYPE)
39 /* String is in the ELF string section */
40 #define BTF_STR_TBL_ELF_ID(ref) (((ref) >> 31) & 0x1)
41 #define BTF_STR_OFFSET(ref) ((ref) & BTF_MAX_NAME_OFFSET)
45 /* "info" bits arrangement
46 * bits 0-15: vlen (e.g. # of struct's members)
48 * bits 24-28: kind (e.g. int, ptr, array...etc)
53 /* "size" is used by INT, ENUM, STRUCT and UNION.
54 * "size" tells the size of the type it is describing.
56 * "type" is used by PTR, TYPEDEF, VOLATILE, CONST and RESTRICT.
57 * "type" is a type_id referring to another type.
65 #define BTF_INFO_KIND(info) (((info) >> 24) & 0x1f)
66 #define BTF_INFO_ISROOT(info) (!!(((info) >> 24) & 0x80))
67 #define BTF_INFO_VLEN(info) ((info) & 0xffff)
69 #define BTF_KIND_UNKN 0 /* Unknown */
70 #define BTF_KIND_INT 1 /* Integer */
71 #define BTF_KIND_PTR 2 /* Pointer */
72 #define BTF_KIND_ARRAY 3 /* Array */
73 #define BTF_KIND_STRUCT 4 /* Struct */
74 #define BTF_KIND_UNION 5 /* Union */
75 #define BTF_KIND_ENUM 6 /* Enumeration */
76 #define BTF_KIND_FWD 7 /* Forward */
77 #define BTF_KIND_TYPEDEF 8 /* Typedef */
78 #define BTF_KIND_VOLATILE 9 /* Volatile */
79 #define BTF_KIND_CONST 10 /* Const */
80 #define BTF_KIND_RESTRICT 11 /* Restrict */
81 #define BTF_KIND_MAX 11
82 #define NR_BTF_KINDS 12
84 /* For some specific BTF_KIND, "struct btf_type" is immediately
85 * followed by extra data.
88 /* BTF_KIND_INT is followed by a u32 and the following
89 * is the 32 bits arrangement:
91 #define BTF_INT_ENCODING(VAL) (((VAL) & 0xff000000) >> 24)
92 #define BTF_INT_OFFSET(VAL) (((VAL & 0x00ff0000)) >> 16)
93 #define BTF_INT_BITS(VAL) ((VAL) & 0x0000ffff)
95 /* Attributes stored in the BTF_INT_ENCODING */
96 #define BTF_INT_SIGNED 0x1
97 #define BTF_INT_CHAR 0x2
98 #define BTF_INT_BOOL 0x4
99 #define BTF_INT_VARARGS 0x8
101 /* BTF_KIND_ENUM is followed by multiple "struct btf_enum".
102 * The exact number of btf_enum is stored in the vlen (of the
103 * info in "struct btf_type").
110 /* BTF_KIND_ARRAY is followed by one "struct btf_array" */
117 /* BTF_KIND_STRUCT and BTF_KIND_UNION are followed
118 * by multiple "struct btf_member". The exact number
119 * of btf_member is stored in the vlen (of the info in
120 * "struct btf_type").
125 __u32 offset; /* offset in bits */
128 #endif /* _UAPI__LINUX_BTF_H__ */